Patents by Inventor Irfan Rahim

Irfan Rahim has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20130043536
    Abstract: One embodiment relates to a buffered transistor device. The device includes a buffered vertical fin-shaped structure formed in a semiconductor substrate. The vertical fin-shaped structure includes at least an upper semiconductor layer, a buffer region, and at least part of a well region. The buffer region has a first doping polarity, and the well region has a second doping polarity which is opposite to the first doping polarity. At least one p-n junction that at least partially covers a horizontal cross section of the vertical fin-shaped structure is formed between the buffer and well regions. Other embodiments, aspects, and features are also disclosed.
    Type: Application
    Filed: August 19, 2011
    Publication date: February 21, 2013
    Inventors: Irfan RAHIM, Jeffrey T. WATT, Yanzhong XU, Lin-Shih LIU
  • Patent number: 8369175
    Abstract: Integrated circuits may include memory elements that are provided with voltage overstress protection. One suitable arrangement of a memory cell may include a latch with two cross-coupled inverters. Each of the two cross-coupled inverters may be coupled between first and second power supply lines and may include a transistor with a gate that is connected to a separate power supply line. Another suitable memory cell arrangement may include three cross-coupled circuits. Two of the three circuits may be powered by a first positive power supply line, while the remaining circuit may be powered by a second positive power supply line. These memory cells may be used to provide an elevated positive static control signal and a lowered ground static control signal to a corresponding pass gate. These memory cells may include access transistors and read buffer circuits that are used during read/write operations.
    Type: Grant
    Filed: September 1, 2010
    Date of Patent: February 5, 2013
    Assignee: Altera Corporation
    Inventors: Lin-Shih Liu, Andy L. Lee, Ping-Chen Liu, Irfan Rahim, Srinivas Perisetty
  • Publication number: 20130002287
    Abstract: In an exemplary embodiment, an apparatus includes a first set of circuit elements and a second set of circuit elements. The first set of circuit elements is used in a first configuration of the apparatus, and the second set of circuit elements is used in a second configuration of the apparatus. The first configuration of the apparatus is switched to the second configuration of the apparatus in order to improve reliability of the apparatus.
    Type: Application
    Filed: June 30, 2011
    Publication date: January 3, 2013
    Inventors: Bruce B. Pedersen, Irfan Rahim
  • Patent number: 8289755
    Abstract: Memory elements are provided that exhibit immunity to soft error upsets. The memory elements may have cross-coupled inverters. The inverters may be implemented using programmable Schmitt triggers. The memory elements may be locked and unlocked by providing appropriate power supply voltages to the Schmitt trigger. The memory elements may each have four inverter-like transistor pairs that form a bistable element, at least one address transistor, and at least one write enable transistor. The write enable transistor may bridge two of the four nodes. The memory elements may be locked and unlocked by turning the write enable transistor on and off. When a memory element is unlocked, the memory element is less resistant to changes in state, thereby facilitating write operations. When the memory element is locked, the memory element may exhibit enhanced immunity to soft error upsets.
    Type: Grant
    Filed: September 30, 2009
    Date of Patent: October 16, 2012
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Jeffrey T. Watt, Andy L. Lee, Myron Wai Wong, William Bradley Vest
  • Patent number: 8138797
    Abstract: Asymmetric transistors such as asymmetric pass transistors may be formed on an integrated circuit. The asymmetric transistors may have gate structures. Symmetric pocket implants may be formed in source-drains on opposing sides of each transistor gate structure. Selective heating may be used to asymmetrically diffuse the implants. Selective heating may be implemented by patterning the gate structures on a semiconductor substrate so that the spacing between adjacent gate structures varies. A given gate structure may be located between first and second adjacent gate structures spaced at different respective distances from the given gate structure. A larger gate structure spacing leads to a greater substrate temperature rise than a smaller gate structure spacing. The pocket implant diffuses more in portions of the substrate with the greater temperature rise, producing asymmetric transistors.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: March 20, 2012
    Assignee: Altera Corporation
    Inventors: Jun Liu, Albert Ratnakumar, Mark T. Chan, Irfan Rahim
  • Patent number: 8138786
    Abstract: A programmable logic device (PLD) includes a delay circuit and a body-bias generator. The delay circuit has a delay configured to represent a delay of user circuit implement in the PLD. The body-bias generator is configured to adjust the body bias of a transistor within the user circuit. The body-bias generator adjusts the body bias of the transistor in response to a level derived from the signal propagation delay of the delay circuit.
    Type: Grant
    Filed: July 31, 2009
    Date of Patent: March 20, 2012
    Assignee: Altera Corporation
    Inventors: David Lewis, Vaughn Betz, Irfan Rahim, Peter McElheny, Yow-Juang W. Liu, Bruce Pedersen
  • Patent number: 8089744
    Abstract: An integrated circuit (IC) includes a multiple-finger transistor structure. The multiple-finger transistor structure includes one transistor configured as a ballasted device. The multiple-finger transistor structure further includes a second transistor configured as a trigger device for the ballasted device.
    Type: Grant
    Filed: August 24, 2005
    Date of Patent: January 3, 2012
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Cheng Hsiung Huang, Yow-Juang Bill Liu, Jeffrey T. Watt, Hugh Sung-Ki O
  • Patent number: 8081502
    Abstract: An integrated circuit with memory elements is provided. The memory elements may have memory element transistors with body terminals. Body bias control circuitry may supply body bias voltages that strengthen or weaken memory element transistors to improve read and write margins. The body bias control circuitry may dynamically control body bias voltages so that time-varying body bias voltages are supplied to memory element transistors. Address transistors and latch transistors in the memory elements may be selectively strengthened and weakened. Process variations may be compensated by weakening fast transistors and strengthening slow transistors with body bias adjustments.
    Type: Grant
    Filed: December 29, 2008
    Date of Patent: December 20, 2011
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Jun Liu, Andy L. Lee, William Bradley Vest, Lu Zhou, Qi Xiang, Yanzhong Yu, Jeffrey Xiaoqi Tung, Albert Ratnakumar
  • Patent number: 8072237
    Abstract: Integrated circuits are provided with circuitry such as multiplexers that can be selectively configured to route different adjustable power supply voltages to different circuit blocks on the integrated circuits. The circuit blocks may contain memory elements that are powered by the power supply voltages and that provide corresponding static output control signals at magnitudes that are determined by the power supply voltages. The control signals from the memory elements may be applied to the gates of transistors in the circuit blocks. Logic on an integrated circuit may be powered at a given power supply voltage level. The memory elements may provide their output signals at overdrive voltage levels that are elevated with respect to the given power supply voltage level. Memory elements associated with circuit blocks that contain critical paths can be overdriven at voltages that are larger than memory elements associated with circuit blocks that contain noncritical paths.
    Type: Grant
    Filed: June 4, 2009
    Date of Patent: December 6, 2011
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Andy L. Lee
  • Patent number: 8030962
    Abstract: Integrated circuits such as programmable logic device integrated circuits are provided that have configuration random-access memory elements. The configuration random-access memory elements are loaded with configuration data to customize programmable logic on the integrated circuits. Each memory element has a capacitor that stores data for that memory element. A pair of cross-coupled inverters are connected to the capacitor. The inverters ensure that the memory elements produce output control signals with voltages than range from one power supply rail to another. Each configuration random-access memory element may have a clear transistor. The capacitor may be formed in a dielectric layer that lies above the transistors of the inverters, the address transistor, and the clear transistor. The inverters may be powered with an elevated power supply voltage.
    Type: Grant
    Filed: August 25, 2010
    Date of Patent: October 4, 2011
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Andy L. Lee, Myron Wai Wong, William Bradley Vest, Jeffrey T. Watt
  • Patent number: 7920410
    Abstract: Memory elements are provided that exhibit immunity to soft error upset events when subjected to radiation strikes such as high-energy atomic particle strikes. The memory elements may each have four inverter-like transistor pairs that form a bistable element and a pair of address transistors. There may be four nodes in the transistor each of which is associated with a respective one of the four inverter-like transistor pairs. There may be two control transistors each of which is coupled between the transistors in a respective one of the inverter-like transistor pairs. During data writing operations, the two control transistors may be turned off to temporarily decouple the transistors in two of the four inverter-like transistor pairs.
    Type: Grant
    Filed: February 23, 2009
    Date of Patent: April 5, 2011
    Assignee: Altera Corporation
    Inventors: Andy L. Lee, Irfan Rahim, Lu Zhou, Madhuri Mailavaram, Srinivas Perisetty
  • Patent number: 7902611
    Abstract: An integrated circuit is provided with transistor body regions that may be independently biased. Some of the bodies may be forward body biased to lower threshold voltages and increase transistor switching speed. Some of the bodies may be reverse body biased to increase threshold voltages and decrease leakage current. The integrated circuit may be formed on a silicon substrate. Body bias isolation structures may be formed in the silicon substrate to isolate the bodies from each other. Body bias isolation structures may be formed from shallow trench isolation trenches. Doped regions may be formed at the bottom of the trenches using ion implantation. Oxide may be used to fill the trenches above the doped region. A deep well may be formed under the body regions. The deep well may contact the doped regions that are formed at the bottom of the trenches.
    Type: Grant
    Filed: November 27, 2007
    Date of Patent: March 8, 2011
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Bradley Jensen, Peter J. McElheny
  • Patent number: 7858469
    Abstract: The present invention is a trigger device useful, for example, in triggering an SCR in an ESD protection circuit. Illustratively, an NMOS trigger device comprises a gate and heavily doped P and N regions in a P-well on opposite sides of the gate. A first N type source/drain extension and a first P-type pocket region extend from the P region toward the N region with the pocket region located under the source/drain extension and extending under the gate. A second N-type source/drain extension and a second P-type pocket region extend from the N region toward the P region with the pocket region located under the source/drain extension and extending under the gate. Preferably, the gate itself is heavily doped so that one half of the gate on the side adjacent the heavily doped P region is also heavily doped with dopants of P-type conductivity and the other half of the gate on the side adjacent the heavily doped N region is also heavily doped with dopants of N-type conductivity.
    Type: Grant
    Filed: September 24, 2009
    Date of Patent: December 28, 2010
    Assignee: Altera Corporation
    Inventors: Jeffrey Watt, Irfan Rahim
  • Publication number: 20100321984
    Abstract: Integrated circuits such as programmable logic device integrated circuits are provided that have configuration random-access memory elements. The configuration random-access memory elements are loaded with configuration data to customize programmable logic on the integrated circuits. Each memory element has a capacitor that stores data for that memory element. A pair of cross-coupled inverters are connected to the capacitor. The inverters ensure that the memory elements produce output control signals with voltages than range from one power supply rail to another. Each configuration random-access memory element may have a clear transistor. The capacitor may be formed in a dielectric layer that lies above the transistors of the inverters, the address transistor, and the clear transistor. The inverters may be powered with an elevated power supply voltage.
    Type: Application
    Filed: August 25, 2010
    Publication date: December 23, 2010
    Inventors: Irfan Rahim, Andy L. Lee, Myron Wai Wong, William Bradley Vest, Jeffrey T. Watt
  • Patent number: 7800400
    Abstract: Integrated circuits such as programmable logic device integrated circuits are provided that have configuration random-access memory elements. The configuration random-access memory elements are loaded with configuration data to customize programmable logic on the integrated circuits. Each memory element has a capacitor that stores data for that memory element. A pair of cross-coupled inverters are connected to the capacitor. The inverters ensure that the memory elements produce output control signals with voltages than range from one power supply rail to another. Each configuration random-access memory element may have a clear transistor. The capacitor may be formed in a dielectric layer that lies above the transistors of the inverters, the address transistor, and the clear transistor. The inverters may be powered with an elevated power supply voltage.
    Type: Grant
    Filed: January 12, 2007
    Date of Patent: September 21, 2010
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Andy L. Lee, Myron Wai Wong, William Bradley Vest, Jeffrey T. Watt
  • Patent number: 7800402
    Abstract: A programmable logic device integrated circuit or other integrated circuit may have logic circuitry that produces data signals. The data signals may be routed to other logic circuits through interconnects. The interconnects may be programmable. A level recovery circuit may be used at the end of each interconnect line to strengthen the transmitted data signal. The level recovery circuit that is attached to a given interconnect line may produce true and complementary versions of the data signal that is on that interconnect line. Level shifting circuitry may be provided to boost the data signals on the interconnects. Each interconnect line may have a level shifter circuit that receives the true and complementary versions of a data signal and that produces corresponding boosted true and complementary versions of the data signal. The boosted signals may be provided to the control inputs of complementary-metal-oxide-semiconductor transistor pass gates in programmable look-up table circuitry.
    Type: Grant
    Filed: November 5, 2007
    Date of Patent: September 21, 2010
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Sriram Muthukumar, William Bradley Vest, Myron Wai Wong
  • Patent number: 7741716
    Abstract: Integrated circuit bond pads are provided for forming wire bonds to integrated circuit package pins. Each pad uses a bond pad structure that provides room for under-pad circuitry. The under-pad circuitry can be connected to other circuitry on the integrated circuit, thereby providing efficient use of circuit real estate. The bond pad structures are formed in the dielectric stack portion of the integrated circuit using dummy bond pads and bond pad support structures. Bond pad support structures may be formed from metal in metal interconnect layers. Vias may be used to connect the bond pad support structures to each other and to the dummy bond pads. Bond pad support structures may be formed in a polysilicon layer at the bottom of the dielectric stack. A contact layer contains metal plugs that connect the polysilicon bond pad support structures to the lowermost metal-layer bond pad support structures.
    Type: Grant
    Filed: November 8, 2005
    Date of Patent: June 22, 2010
    Assignee: Altera Corporation
    Inventors: Girish Venkitachalam, Irfan Rahim, Peter John McElheny
  • Publication number: 20100148304
    Abstract: Power supply decoupling capacitors are provided for integrated circuits. The decoupling capacitors may be distributed in clusters amongst powered circuit components. Each cluster may contain a number of individual capacitor cells that are connected in parallel. Each capacitor cell may contain a capacitor and a resistor connected in series with the capacitor. The capacitors may be metal-insulator-metal (MIM) capacitors. The resistor in each cell may limit the current through an individual capacitor in the event of a short in the capacitor due to a dielectric defect.
    Type: Application
    Filed: December 11, 2008
    Publication date: June 17, 2010
    Inventors: Irfan Rahim, William Bradley Vest, Myron Wai Wong
  • Patent number: 7639033
    Abstract: The present invention optimizes the performance of integrated circuits by adjusting the circuit operating voltage using feedback on process/product parameters. To determine a desired value for the operating voltage of an integrated circuit, a preferred embodiment provides for on-wafer probing of one or more reference circuit structures to measure at least one electrical or operational parameter of the one or more reference circuit structures; determining an adjusted value for the operating voltage based on the measured parameter; and establishing the adjusted value as the desired value for the operating voltage. The reference circuit structures may comprise process control monitor structures or structures in other integrated circuits fabricated in the same production run. In an alternative embodiment, the one or more parameters are directly measured from the integrated circuit whose operating voltage is being adjusted.
    Type: Grant
    Filed: December 13, 2006
    Date of Patent: December 29, 2009
    Assignee: Altera Corporation
    Inventors: Irfan Rahim, Peter McElheny, John Costello
  • Publication number: 20090302421
    Abstract: A deep trench capacitor includes a trench having walls and a floor. The deep trench capacitor also includes a layer of gate oxide on the walls and floor. Gate polysilicon is deposited over the gate oxide.
    Type: Application
    Filed: June 9, 2008
    Publication date: December 10, 2009
    Inventors: Charu Sardana, Bradley Jensen, Irfan Rahim, Jeffrey T. Watt